Abhay Ashtekar
Encyclopedia
Abhay Vasant Ashtekar (born July 5, 1949) is an Indian theoretical physicist. He is the Eberly Professor of Physics and the Director of the Institute for Gravitational Physics and Geometry at Pennsylvania State University
. As the creator of Ashtekar variables
, he is one of the founders of loop quantum gravity
and its subfield loop quantum cosmology
. He has also written a number of descriptions of loop quantum gravity that are accessible to non-physicists. In 1999, Ashtekar and his colleagues were able to calculate the entropy
for a black hole
, matching a legendary 1974 prediction by Hawking
. Oxford mathematical physicist Roger Penrose
has described Ashtekar's approach to quantum gravity
as "The most important of all the attempts at 'quantizing' general relativity."
, in the state of Maharashtra
, India
. After completing his undergraduate education in India, Ashtekar enrolled in the graduate program for gravitation
at the University of Texas at Austin
. He went on to complete his Ph.D. at the University of Chicago
under Prof. Robert Geroch
in 1974 (thesis titled: "Asymptotic Structure of the Gravitational Field at Spatial Infinity") and held several appointments at Oxford, Paris
, Syracuse
before settling at Penn State.
He married Christine Clarke in 1986 and the two have a son, Neil.
Pennsylvania State University
The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the state of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service...
. As the creator of Ashtekar variables
Ashtekar variables
In theoretical physics, Ashtekar variables represent an unusual way to rewrite the metric on the three-dimensional spatial slices in terms of a SU gauge field and its complementary variable...
, he is one of the founders of loop quantum gravity
Loop quantum gravity
Loop quantum gravity , also known as loop gravity and quantum geometry, is a proposed quantum theory of spacetime which attempts to reconcile the theories of quantum mechanics and general relativity...
and its subfield loop quantum cosmology
Loop quantum cosmology
Loop quantum cosmology is a finite, symmetry-reduced model of loop quantum gravity that predicts a quantum bridge between contracting and expanding cosmological branches...
. He has also written a number of descriptions of loop quantum gravity that are accessible to non-physicists. In 1999, Ashtekar and his colleagues were able to calculate the entropy
Entropy
Entropy is a thermodynamic property that can be used to determine the energy available for useful work in a thermodynamic process, such as in energy conversion devices, engines, or machines. Such devices can only be driven by convertible energy, and have a theoretical maximum efficiency when...
for a black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
, matching a legendary 1974 prediction by Hawking
Stephen Hawking
Stephen William Hawking, CH, CBE, FRS, FRSA is an English theoretical physicist and cosmologist, whose scientific books and public appearances have made him an academic celebrity...
. Oxford mathematical physicist Roger Penrose
Roger Penrose
Sir Roger Penrose OM FRS is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College...
has described Ashtekar's approach to quantum gravity
Quantum gravity
Quantum gravity is the field of theoretical physics which attempts to develop scientific models that unify quantum mechanics with general relativity...
as "The most important of all the attempts at 'quantizing' general relativity."
Biography
Abhay Ashtekar grew up in several cities, including MumbaiMumbai
Mumbai , formerly known as Bombay in English, is the capital of the Indian state of Maharashtra. It is the most populous city in India, and the fourth most populous city in the world, with a total metropolitan area population of approximately 20.5 million...
, in the state of Maharashtra
Maharashtra
Maharashtra is a state located in India. It is the second most populous after Uttar Pradesh and third largest state by area in India...
, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. After completing his undergraduate education in India, Ashtekar enrolled in the graduate program for gravitation
Gravitation
Gravitation, or gravity, is a natural phenomenon by which physical bodies attract with a force proportional to their mass. Gravitation is most familiar as the agent that gives weight to objects with mass and causes them to fall to the ground when dropped...
at the University of Texas at Austin
University of Texas at Austin
The University of Texas at Austin is a state research university located in Austin, Texas, USA, and is the flagship institution of the The University of Texas System. Founded in 1883, its campus is located approximately from the Texas State Capitol in Austin...
. He went on to complete his Ph.D. at the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
under Prof. Robert Geroch
Robert Geroch
Robert Geroch is a theoretical physicist and professor at the University of Chicago. He has worked prominently on general relativity and mathematical physics and has promoted the use of category theory in mathematics and physics. He was the Ph.D. supervisor for Abhay Ashtekar.Geroch obtained his Ph.D...
in 1974 (thesis titled: "Asymptotic Structure of the Gravitational Field at Spatial Infinity") and held several appointments at Oxford, Paris
University of Paris
The University of Paris was a university located in Paris, France and one of the earliest to be established in Europe. It was founded in the mid 12th century, and officially recognized as a university probably between 1160 and 1250...
, Syracuse
Syracuse University
Syracuse University is a private research university located in Syracuse, New York, United States. Its roots can be traced back to Genesee Wesleyan Seminary, founded by the Methodist Episcopal Church in 1832, which also later founded Genesee College...
before settling at Penn State.
He married Christine Clarke in 1986 and the two have a son, Neil.
Books
- A. Magnon and A. Ashtekar, Translation from French of Elie Cartan's work, "Sur les Varietes a Connexion Affine et la Relativite Generale" with a Commentary and Foreword by A. Trautman. Bibliopolis, Naples, 1986, 199 pages.
- A. Ashtekar, Asymptotic Quantization. Bibliopolis, Naples, 1987, 107 pages.
- A. Ashtekar, (with invited contributions) New Perspectives in Canonical Gravity.Bibliopolis, Naples, 1988, 324 pages.
- A. Ashtekar and J. Stachel, Editors; Conceptual Problems of Quantum Gravity. Proceedings of the 1988 Osgood Hill Conference (Birkhauser, N. Y., 1991), 602 pages.
- A. Ashtekar, Lectures on Non-perturbative Canonical Gravity, (Notes prepared in collaboration with R.S. Tate), (World Scientific Singapore, 1991), 334 pages.
- A. Ashtekar, R.C. Cohen, D. Howard, J. Renn, S. Sarkar and A. Shimony (Editors), Revisiting the Foundations of Relativistic Physics, Festschrift in honor of John Stachel, Boston Studies in Philosophy of Science, Volume 234, (Kluwer Academic, 2003).
External links
- Abhay Ashtekar's homepage
- Ashtekar's publication on ArXivArXivThe arXiv |Chi]], χ) is an archive for electronic preprints of scientific papers in the fields of mathematics, physics, astronomy, computer science, quantitative biology, statistics, and quantitative finance which can be accessed online. In many fields of mathematics and physics, almost all...